1. Field of the Invention
This invention relates generally to the field of workpiece transporting systems wherein a workpiece carrier is moved along a conveyor from station to station as various assembly, machining, processing or test operations are performed on workpieces supported thereon. Transport systems of the indicated type are capable of synchronous or non-synchronous pallet transport, i.e., the pallets can move dependently or independently of each other.
More particularly, the invention relates to lifting and rotating devices for use with the conveyors. These devices lift a workpiece carrier off the conveyor system and position the same for having work performed on the workpiece by a robot or the like.
2. Description of the Prior Art
There have been provided lifting and rotating devices of the indicated type. Typical of these prior art devices is the "lift and turning unit" of Bosch, GmbH which is constructed for the lifting and turning of workpiece pallets by 0-180.degree. within steps of 15.degree.. This device operates by lifting the pallet from the conveyor belt, turning the pallet by 0-180.degree. within steps of 15.degree., reversing to 0.degree. and returning the pallet to the conveyor belt. However, these prior art devices are not entirely satisfactory since they are limited in the precision of the positioning of the workpiece relative to the work station and there is limited control over the rotational movement.